In the modern information society people are more and more dependent on telecommunication networks and services offered by them. Utilizing telecommunication networks has been experienced to be so important that people no more want to be dependent on the bonds of traditional wired network. This is why a great number of people already have wireless mobile stations, e.g. GSM stations, which are mainly used for normal speech communication.
To a more increasing extent people have become dependent on even other telecommunication services available, such as telefax, electronic mail, Internet and other information transfer services. When one is used to these services in the traditional office environment, they are difficult to give up for example when leaving for a business trip.
In order to manage when on the road, as easily as possible, e.g. one's time and meetings, so called electronic notebooks have been developed. They are generally called PDA (Personal Digital Assistant), PCD (Personal Communication Device) and PIC (Personal Intelligent Communicator) devices. These devices are typically of the size of a largish pocket calculator and often equipped with a touch screen. The user can with a plastic tip pencil designed for this particular purpose, or even by touching the screen with fingers, write text and figures on the screen, from which the device interprets the information given. In addition to that, the user can control the functions of the device by touching menus which the device generates in the display. Typical services made possible by PDA devices are e.g. calendar and notebook services, reminding of agreed meetings by e.g. an acoustic signal, and a phone book from which information can be searched based upon a person's or company's name or other corresponding information. Additionally, PDA devices often also have a pocket calculator function.
When the features of a mobile station, a computer and a typical PDA device are integrated and packed in a very compact size, the result is a very versatile wireless data communication terminal. An example of a device comprising a touch screen known from PDA devices, DOS operating system known from computers, and a traditional mobile station, is presented in U.S. Pat. No. 5,422,656. With the device according to said patent publication it is possible to use various telecommunication services, e.g. to use it as a normal mobile telephone, to transmit and receive telefax messages or to use it as a pocket calculator.
The solutions presented in said US patent yet have their disadvantages. Because the device is based on DOS operating system known from computers, the device must be at commissioning be initialized by loading the operating system in the processor of the device. After this, the first service, e.g. mobile telephone service, is loaded in a memory. When the mobile telephone service is initialized, it further initializes the necessary auxiliary components, and contacts a base station. All these initializing operations are time consuming and it takes quite a long time until the device is prepared for wireless communication after switch-on.
When shifting from one service to another, e.g. from said telefax service to said phone service, the user must first save the eventual information used by him in the previous service in order not to loose it when starting a new service. This is laborious and can easily be forgotten in a hurry. This will happen e.g. when the user is writing a telefax message and answers an incoming call too hurriedly. Alike when initializing the device for the first time, also all new services must be separately loaded in the memory of the device before they can be used. This downgrades the usability of services and does not offer a handy method for transferring information from one service to another. Neither does the operating system used make it possible to use several services simultaneously.
A very big disadvantage is also, that information which has not been stored, is lost when battery voltage drops too low, or if for some other reason power supply is cut off or disturbed. This happens e.g. if the battery gets loose or if there is poor contact in battery terminals.
Now a multi-service mobile station has been invented, with which at least part of the above mentioned problems can be avoided.